runsc: Support runsc kill multi-container.

Now, we can kill individual containers rather than the entire sandbox.

PiperOrigin-RevId: 211748106
Change-Id: Ic97e91db33d53782f838338c4a6d0aab7a313ead

2 files changed, 18 insertions, 10 deletions

diff --git a/runsc/boot/controller.go b/runsc/boot/controller.go
index ec1110059..45aa255c4 100644
--- a/runsc/boot/controller.go
+++ b/runsc/boot/controller.go
@@ -22,7 +22,6 @@ import (
 	specs "github.com/opencontainers/runtime-spec/specs-go"
 	"gvisor.googlesource.com/gvisor/pkg/control/server"
 	"gvisor.googlesource.com/gvisor/pkg/log"
-	"gvisor.googlesource.com/gvisor/pkg/sentry/arch"
 	"gvisor.googlesource.com/gvisor/pkg/sentry/control"
 	"gvisor.googlesource.com/gvisor/pkg/sentry/fs"
 	"gvisor.googlesource.com/gvisor/pkg/sentry/kernel"
@@ -387,13 +386,5 @@ type SignalArgs struct {
 // Signal sends a signal to the init process of the container.
 func (cm *containerManager) Signal(args *SignalArgs, _ *struct{}) error {
 	log.Debugf("containerManager.Signal")
-	// TODO: Use the cid and send the signal to the init
-	// process in theat container. Currently we just signal PID 1 in the
-	// sandbox.
-	si := arch.SignalInfo{Signo: args.Signo}
-	t := cm.l.k.TaskSet().Root.TaskWithID(1)
-	if t == nil {
-		return fmt.Errorf("cannot signal: no task with id 1")
-	}
-	return t.SendSignal(&si)
+	return cm.l.signal(args.CID, args.Signo)
 }
diff --git a/runsc/boot/loader.go b/runsc/boot/loader.go
index 2733c4d69..ae2226e12 100644
--- a/runsc/boot/loader.go
+++ b/runsc/boot/loader.go
@@ -31,6 +31,7 @@ import (
 	"gvisor.googlesource.com/gvisor/pkg/abi/linux"
 	"gvisor.googlesource.com/gvisor/pkg/cpuid"
 	"gvisor.googlesource.com/gvisor/pkg/log"
+	"gvisor.googlesource.com/gvisor/pkg/sentry/arch"
 	"gvisor.googlesource.com/gvisor/pkg/sentry/inet"
 	"gvisor.googlesource.com/gvisor/pkg/sentry/kernel"
 	"gvisor.googlesource.com/gvisor/pkg/sentry/kernel/auth"
@@ -576,3 +577,19 @@ func newEmptyNetworkStack(conf *Config, clock tcpip.Clock) (inet.Stack, error) {
 		panic(fmt.Sprintf("invalid network configuration: %v", conf.Network))
 	}
 }
+
+func (l *Loader) signal(cid string, signo int32) error {
+	l.mu.Lock()
+	tgid, ok := l.containerRootTGIDs[cid]
+	l.mu.Unlock()
+	if !ok {
+		return fmt.Errorf("failed to signal container %q: no such container", cid)
+	}
+
+	// The thread group ID of a process is the leading task's thread ID.
+	t := l.k.TaskSet().Root.TaskWithID(tgid)
+	if t == nil {
+		return fmt.Errorf("cannot signal: no task with ID %d", tgid)
+	}
+	return t.SendSignal(&arch.SignalInfo{Signo: signo})
+}